fix(GRAPHQL): fix query rewriting for multiple order on nested field. (…

…#7523)

We were not adding the , in-between multiple orders in query rewriting for the nested field.
For example the order given in this filter

posts(filter: { title: { anyofterms: "GraphQL" } }, order: { asc: numLikes, then: { desc: title } }, first: 10, offset: 10) got written to below dgraph statement

Author.posts : Author.posts @filter(anyofterms(Post.title, "GraphQL")) (orderasc: Post.numLikesorderdesc: Post.title, first: 10, offset: 10)

where there is no comma between two orders. We have fixed it in this PR.

graphql/dgraph/graphquery.go

@@ -219,7 +219,7 @@ func writeOrderAndPage(b *strings.Builder, query *gql.GraphQuery, root bool) {
 	var wroteOrder, wroteFirst bool
 
 	for _, ord := range query.Order {
-		if root {
+		if root || wroteOrder {
 			x.Check2(b.WriteString(", "))
 		}
 		if ord.Desc {

graphql/resolve/query_test.yaml

@@ -1351,6 +1351,29 @@
       }
     }
 
+-
+  name: "Deep filter with multiple order, first and offset"
+  gqlquery: |
+    query {
+      queryAuthor {
+        name
+        posts(filter: { title: { anyofterms: "GraphQL" } }, order: { asc: numLikes, then: { desc: title } }, first: 10, offset: 10) {
+          title
+        }
+      }
+    }
+  dgquery: |-
+    query {
+      queryAuthor(func: type(Author)) {
+        Author.name : Author.name
+        Author.posts : Author.posts @filter(anyofterms(Post.title, "GraphQL")) (orderasc: Post.numLikes, orderdesc: Post.title, first: 10, offset: 10) {
+          Post.title : Post.title
+          dgraph.uid : uid
+        }
+        dgraph.uid : uid
+      }
+    }
+
 -
   name: "Float with large exponentiation"
   gqlquery: |